Method and device for increasing fin device density for unaligned fins

ABSTRACT

A method for generating a layout for a device having FinFETs from a first layout for a device having planar transistors is disclosed. A plurality of elongate mandrels is defined in a plurality of active regions. Where adjacent active regions are partially-parallel and within a specified minimum spacing, connective elements are added to a portion of the space between the adjacent active regions to connect the mandrel ends from one active region to another active region.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of U.S. Application Ser. No. 61/412,846, filed on Nov. 12, 2010, which is incorporated herein by reference in its entirety.

The present application is related to U.S. patent application Ser. Nos. 12/707,788, filed on Feb. 18, 2010, (Docket Nos. TSMC2008-0432, T5057-R007U), titled MEMORY POWER GATING CIRCUIT AND METHODS; 12/758,426, filed on Apr. 12, 2010, (Docket Nos. TSMC2008-0582, T5057-Y048U), titled FINFETS AND METHODS FOR FORMING THE SAME; 12/731,325, filed on Mar. 25, 2010, (Docket Nos. TSMC2008-0597, T5057-B033U), titled ELECTRICAL FUSE AND RELATED APPLICATIONS; 12/724,556, filed on Mar. 16, 2010, (Docket Nos. TSMC2008-0598, T5057-K002U), titled ELECTRICAL ANTI-FUSE AND RELATED APPLICATIONS; 12/757,203, filed on Apr. 9, 2010, (Docket Nos. TSMC2009-0148, T5057-Y085U), titled STI STRUCTURE AND METHOD OF FORMING BOTTOM VOID IN SAME; 12/797,839, filed on Jun. 10, 2010, (Docket Nos. TSMC2009-0278, T5057-K099U), titled FIN STRUCTURE FOR HIGH MOBILITY MULTIPLE-GATE TRANSISTOR; 12/831,842, filed on Jul. 7, 2010, (Docket Nos. TSMC2009-0343, T5057-Y093U), titled METHOD FOR FORMING HIGH GERMANIUM CONCENTRATION SiGe STRESSOR; 12/761,686, filed on Apr. 16, 2010, (Docket Nos. TSMC2009-0442, T5057-Y125U), titled FINFETS AND METHODS FOR FORMING THE SAME; 12/766,233, filed on Apr. 23, 2010, (Docket Nos. TSMC2009-0444, T5057-K123U), titled FIN FIELD EFFECT TRANSISTOR; 12/757,271, filed on Apr. 9, 2010, (Docket Nos. TSMC2009-0445, T5057-Y113U), titled ACCUMULATION TYPE FINFET, CIRCUITS AND FABRICATION METHOD THEREOF; 12/694,846, filed on Jan. 27, 2010, (Docket Nos. TSMC2009-0646, T5057-Y165), titled INTEGRATED CIRCUITS AND METHODS FOR FORMING THE SAME; 12/638,958, filed on Dec. 14, 2009, (Docket Nos. TSMC2009-0738, T5057-B166), titled METHOD OF CONTROLLING GATE THICKNESS IN FORMING FINFET DEVICES; 12/768,884, filed on Apr. 28, 2010, (Docket Nos. TSMC2010-0028, T5057-Y228), titled METHODS FOR DOPING FIN FIELD-EFFECT TRANSISTORS; 12/731,411, filed on Mar. 25, 2010, (Docket Nos. TSMC2010-0057, T5057-B218), titled INTEGRATED CIRCUIT INCLUDING FINFETS AND METHODS FOR FORMING THE SAME; 12/775,006, filed on May 6, 2010, (Docket Nos. TSMC2010-0198, T5057-Y246), titled METHOD FOR FABRICATING A STRAINED STRUCTURE; 12/886,713, filed Sep. 21, 2010, (Docket Nos. TSMC2010-0646, T5057-B325), titled METHOD OF FORMING INTEGRATED CIRCUITS; 12/941,509, filed Nov. 8, 2010, (Docket Nos. TSMC2010-0561, T5057-B337), titled MECHANISMS FOR FORMING ULTRA SHALLOW JUNCTION; 12/900,626, filed Oct. 8, 2010, (Docket Nos. TSMC2010-0581, T5057-B330), titled TRANSISTOR HAVING NOTCHED FIN STRUCTURE AND METHOD OF MAKING THE SAME; 12/903,712, filed Oct. 13, 2010, (Docket Nos. TSMC2010-0731, T5057-R350), titled FINFET AND METHOD OF FABRICATING THE SAME; 61/412,846, filed Nov. 12, 2010, (Docket Nos. TSMC2010-0839, T5057-B388PRO), 61/394,418, filed Oct. 19, 2010, (Docket Nos. TSMC2010-0926, T5057-Y351PRO), titled METHODS OF FORMING GATE DIELECTRIC MATERIAL and 61/405,858, filed Oct. 22, 2010, (Docket Nos. TSMC2010-0928, T5057-R368PRO), titled METHODS OF FORMING SEMICONDUCTOR DEVICES; which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The disclosure relates generally to integrated circuit devices, and more particularly to structure and methods for forming fin field-effect transistors (FinFETs).

BACKGROUND

In the rapidly advancing semiconductor manufacturing industry, complementary metal oxide semiconductor (CMOS) FinFET devices may be used in many logic and other applications and are integrated into various different types of semiconductor devices. FinFET devices typically include semiconductor fins with high aspect ratios in which the channel and source/drain regions for the transistor are formed. A gate is formed over and along the sides of a portion of the semiconductor fins. The increased surface area of the channel and source/drain regions in a FinFET results in faster, more reliable and better-controlled semiconductor transistor devices. New advanced designs are created with FinFET structures at the outset with computed-aided design (CAD) layers that define the boundary of each FinFET. As manufacturing processes progress into smaller and smaller technology nodes, devices originally designed in a larger technology node may benefit from manufacture in a smaller technology node in ways such as increased performance, increased efficiencies, and decreased die size. Similarly, devices designed using planar transistors can also reap benefits by manufacture using FinFETs. However, because different design rules apply to planar structure layouts and FinFET structure layouts, converting portions of the device from a planar layout to a FinFET layout by hand may be akin to creating a new design, which is a highly resource intensive process few designers would invest in for an older product.

As such, improved methods for automatically converting older planar structure layouts to FinFET structure layouts continue to be sought.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the following detailed the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 illustrates a flowchart of a method for converting a planar structure layout to a FinFET structure layout in accordance with certain embodiments of the present disclosure.

FIG. 2 illustrates a number of active regions on a layout.

FIG. 3 illustrates a misaligned fin configuration and connective elements according to various embodiments of the present disclosure.

FIG. 4 illustrates an unequal pitch configuration and connective elements according to various embodiments of the present disclosure.

FIG. 5 illustrates an unequal pitch configuration and connective elements according to various embodiments of the present disclosure.

FIG. 6 illustrates various connective elements and layout conversion methods applied to the layout of FIG. 2 according to various embodiments of the present disclosure.

FIG. 7 is a simplified diagrammatic view of a machine that can be used to generate the layout in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The making and using of illustrative embodiments are discussed in detail below. It should be appreciated, however, that the disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Of course, the description may specifically state whether the features are directly in contact with each other. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. The specific embodiments discussed are merely illustrative and do not limit the scope of the invention.

FinFETs use a substantially rectangular fin structure formed generally in one of two ways. In a first method, bulk silicon on a substrate is etched into rectangular fin shape by first patterning and depositing a hardmask layer on the bulk silicon. The hardmask forms a pattern covering the top of the fins. The bulk silicon is then etched to form trenches between the regions covered by the hardmask layer. The trenches are formed into shallow trench isolation (STI) features by depositing a dielectric material, usually silicon oxide, into the trench. The dielectric material is usually deposited in excess to completely cover the fins and optionally the hardmask layer if not already removed. The dielectric material is planarized down to the top surface of the fin/hardmask, and then etched to a level below the top of the fin so that a portion of the fin protrudes above the STI.

In a second method, the STI features are formed first on bulk silicon material by depositing an STI layer and etching trenches into it. The bottoms of the trenches between the STI features are exposed bulk silicon. Silicon is then grown in the trenches to form the fins by using, for example, an epitaxial process. Once a desired fin height is reached, then the STI is etched to a level below the top of the fin to expose a portion of the fin. The bulk silicon material may be a silicon substrate or a deposited silicon such as silicon-on-insulator (SOI) with a barrier oxide (BOX) layer between the SOI and the underlying silicon substrate.

In a variation of the first method, the hardmask for etching into the bulk silicon is formed by a process using mandrels. A photoresist pattern is formed and used to etch a mandrel pattern. A conformal spacer material is then deposited around the mandrel. The conformal spacer is usually formed of a hardmask material forming a spacer sidewall thinner than that of the mandrel. The mandrel material between the spacers is then removed in subsequent etching operations to leave just the spacers behind. Some of the spacers are then used as a hardmask for etching the silicon layers below, forming the fin structures. Using the mandrel/spacer method, thinner fins that are closer together can be formed than an unmodified, conventional first method.

As discussed, a method to automatically convert planar structure layouts to FinFET structure layouts is sought. As discussed above, various performance gains may be garnered by converting a planar transistor to a FinFET. However, for an existing product, the cost of making photomasks for all the layers is very high; hence, it is important to reuse as many photomasks from an existing product as possible. Therefore, it may be necessary to form the FinFETs within the confines of planar transistor structures so that layouts of other layers are not affected. To realize the benefits of using a FinFET structure, the fin density within the confines of planar transistor structures should be maximized. Alternatively, the use of FinFETs and embodiments of the present disclosure may allow the overall layout to decrease in size and hence reduce the size of the die, but with an increased cost of making additional photomasks.

FIG. 1 illustrates a semiconductor process flow 11 to manufacture FinFET structures using planar structure layouts. In operation 13, a first layout is received. The planar structure layout includes defined active regions having sides. FIG. 2 illustrates a portion of a layout including active regions 63-68. The active regions 63-68 are regions of a substrate where transistors (not illustrated) of the example semiconductor device will be formed. It is understood that the active regions 63-68 are merely examples for the sake of facilitating ensuing discussions, and that any number of other active regions may be included in the first layout, and they may have shapes or geometries different from the active regions 63-68.

For the purpose of this disclosure, an active region defines the boundaries on which the fins of a FinFET can form. In operation 15 of FIG. 1, elongate mandrels are defined in each active region. Elongate mandrels are subsequently removed features next to which the spacers are deposited. These spacers are then used as hardmasks for etching underlying silicon to form fins. In some embodiments, the density of fins is maximized by placing the mandrels one spacer thickness away from the edge of the active region. A pitch of the mandrels is specified by the technology node, which defines the smallest feature size achievable. The mandrel pitch is equal to two times the fin pitch, and the mandrel width is about the same as fin spacing.

FIG. 2 also shows a plurality of gate electrode directions 73-78 associated with respective active regions 63-68. For active region 65, the gate electrode direction 75 is shown to be in the x direction as shown in FIG. 2. An elongate direction for the elongate mandrels is selected according to the gate electrode directions 73-78. The mandrels are typically oriented orthogonally, or about 90 degrees, to the gate electrode direction, though a different orientation is possible. For active region 65, for example, the elongate direction of the mandrels may be in the y direction, which is orthogonal to the gate direction 75.

The elongate mandrels may be placed in different active regions with the same pitch or different pitch. Starting from one side of an active region, a first elongate mandrel may be placed adjacent to the edge. From the first, or top, elongate mandrel, the next mandrel may be defined in parallel according to a minimum mandrel pitch. The minimum mandrel pitch is defined by the technology node to be the smallest pitch between features that can be manufactured. Each successive mandrel is spaced apart from one another in a direction perpendicular to the elongate direction according to the minimum mandrel pitch. In many cases, the mandrels are spaced apart in the same direction as the gate electrode. In this way, as mandrels are successively defined from one side of the active region to the opposite side of the active region, the last mandrel may or may not fit in the remaining space. In other words, an area at the opposite side of the active region may be left empty if the last mandrel does not fit. As result, the active region edge on the opposite side may not have a mandrel placed adjacent to the edge.

In some embodiments, the mandrels at the sides sharing the edge with the active regions are defined first, one at each end of the active region. In the space between the end mandrels, a maximum number of mandrels are defined in an equally spaced manner such that the mandrel pitch is not below the minimum mandrel pitch yet the same number of total mandrels in the active region is the same as if the minimum mandrel pitch is used. In other words, the procedure would calculate the total integer number of mandrels that can fit using the minimum mandrel pitch and define the integer number within the active region in an equally spaced manner. In these embodiments, the mandrels pitch may be larger than the minimum mandrel pitch with the same fin density. This embodiment maximizes the number of mandrels in the active region.

In still other embodiments, the number of fins is maximized rather than the number of mandrels. As noted above, the fins are formed by using spacers as hardmasks. Each mandrel results in two fins. If the length of an active region divided by the mandrel pitch results in a decimal number of mandrels that would fit in one active region has a fractional part larger than 0.5, then one additional fin may be included. The additional fin would be formed by a mandrel located outside of the active region instead of inside of the active region. Because locating the mandrel outside of the active region would form an extra spacer and perhaps an extra fin, the extra spacer or fin must be removed in a subsequent process.

In operation 17 of FIG. 1, a minimum distance between nearest sides of adjacent pairs of partially-parallel active regions is determined. FIG. 2 illustrates various relationships between active regions. For example, active regions 65/66, 66/67, 66/63, 63/64, and 67/68 are adjacent pairs. For the purpose of this disclosure, active regions 66/68 or 64/67 are not adjacent pairs. Partially-parallel active regions have mandrels that are parallel to each other and at least partially overlapping nearest sides. For example, active regions 65 and 66 are partially-parallel. Because both 75 and 76 are oriented in the x direction, their mandrels are both oriented in the y direction. Hence the mandrels are parallel. Their nearest sides, the right side of 65 and left side of 66 partially overlap in the x direction, as shown by the hatched area 71 illustrating an overlapping intermediate region 71 between the two adjacent pairs of partially-parallel active regions 65 and 66. In the same way, active regions 66/67, 64/68 and 67/68 are also partially-parallel. However, active regions 63/66 and 63/64 are not partially-parallel because mandrels within these adjacent active regions are oriented orthogonally from each other, although a portion of the nearest sides does overlap.

It is well known that the minimum distance between parallel line segments is the length of a line segment connecting at right angles to the parallel segments. The minimum distance between active regions 65 and 66 is 81. FIG. 2 shows various minimum distances 82 (66/67), 83 (66/63), 84 (63/64), 85 (64/68), and 86 (67/68).

When the minimum distance between nearest sides of adjacent pairs of partially-parallel active regions is below a certain lithography defined minimum spacing, various problems can occur. A pattern forming the mandrels in one active region can interfere with another pattern forming the mandrels in another region. Various optical proximity correction (OPC) methods for enhancing the pattern can increase the possibility of interference by moving the exposed areas even closer together. One possible result is an unintended bridge between two or more mandrels. The bridge may cause electrical abnormalities. Another possible result is particles from irregularly shaped mandrel ends.

In cases where an adjacent active region pair has a minimum distance less than the minimum spacing, the mandrels in the overlapping region are connected in operation 19 of FIG. 1 in accordance with various embodiments of the present disclosure. The specified minimum spacing is related to particular lithography techniques used, the type of feature to be formed, the lithography materials used, and technology node. In addition to a minimum spacing requirement applying to the distance between nearest sides of the active regions, other types of distance limitations may be used. For example, the end-to-end distance between mandrels across the overlapping region may be used instead. Because the mandrels may be unaligned across the overlapping region, the end-to-end or corner-to-corner distance between two of the nearest mandrels across the overlapping region may be larger than the minimum distance.

FIGS. 3-5 show various ways the mandrels may be connected. FIG. 3 illustrate two active regions 301 and 303 with a minimum distance “d” between the nearest sides that is less than a specified minimum spacing. The number of mandrels and mandrel pitch are the same in active regions 301 and 303. A connective element 311 is added to connect ends of mandrel 305 and 309. Successive connective elements are added to connect ends of the succeeding mandrels in each active region. Note that because the mandrel pitches are the same in active regions 301 and 303, the connective elements have the same orientation relative to the mandrels. The connective element 311 has a width not greater than either mandrel between which the connective element connects. In many cases, the connective element has a width that is the same as one or both of the mandrels.

In some embodiments, the mandrels to which the connective elements connect are selected to maximize the acute angle between the connective element and the mandrel. In other words, for horizontal mandrels, the mandrels are chosen so that the connective element is as horizontal as possible to simplify the photolithography operations used to form the connective elements. For example, in FIG. 3, the connective element 311 may connect mandrels 309/305 as shown or 309/307 instead, forming a different angle with the mandrels. Various photolithography operations may limit an angular range for forming the connective elements, for example, to simplify any OPC operations. In certain embodiments, the connective element between mandrel ends is curved instead of straight. The curved connective element may require less OPC processing to produce. Because the connective elements are ultimately removed in subsequent processing, any particular shape may be used as long as no adverse electrical properties result.

FIG. 4 shows a situation where each of an adjacent pair of partially-parallel active regions have different mandrel pitches. With different mandrel pitches, choosing the mandrels between which to make the first connective element connection becomes important because pitch differences will vary the mandrel to connective element angle from connective element to connective element. Where the lithography process limits the range of angles, a next connective element may form an unacceptable angle with one of the mandrels.

FIG. 4 shows a number of connective elements, for example, 411, 415, 423, and 425. According to various embodiments, the end to end distance between various mandrels are determined, and the mandrel pair having a shortest distance between their ends is selected, for example in FIG. 4, the shortest distance between two mandrel ends is that between mandrels 419 and 413, connected by connective element 425. Starting from the mandrel pair 419/413, a connective element is attached to successive ends of each pair of mandrels across the nearest sides (for example, between 417 and 409, between 407 and 421) within the partially-parallel portion (427) of the adjacent pair of partially-parallel active regions 401 and 403. Note that the angle from horizontal increases with respect to further connective elements as compared to the shortest connective element 425. In certain cases, the next connective element may have an angle that cannot be accommodated by the lithography process. In those cases one mandrel should be skipped to form a more horizontal connective element. This embodiment would connect the most number of mandrels without exceeding the lithography angular range for forming the connective elements. Note also mandrel 405 is not connected to another mandrel because it is located outside of the partially-parallel portion 427. While mandrel 429 is located outside of the partially-parallel portion 427, it is optionally connected to mandrel 431 via connective element 415 because mandrel 431 to which it connected is within the partially-parallel portion 427.

FIG. 5 shows yet another connective element configuration in accordance with various embodiments of the present disclosure. In FIG. 5, a central connective element 523 is used with a number of branch connective elements 511 to connect the mandrels from active region 501 to the mandrels from active region 503. In these embodiments, a central connective element is placed in the region between the active regions in a perpendicular direction to the mandrels, or, as usually oriented, parallel to the gate electrode. The mandrels are then extended in a branch connective element toward the central connective element until they connect to the central connective element. In these embodiments, whether the mandrels in the adjacent active regions have the same mandrel pitch is not important, because the branch connective elements connect to the central connective element in the same way, at right angles. Note that it is not necessary that the central connective element is placed in the middle of the partially-parallel portion. FIG. 5 shows mandrel ends from portions outside of the partially-parallel portion connecting to the central connective element. In some embodiments, the central connective element does not extend past the partially-parallel portion and mandrel 505 would not be connected to the central connective element. In certain embodiments, the central connective element has a width not greater than two times that of mandrels in the adjacent pair of partially-parallel active regions to avoid local loading effects. In some embodiments, the central connective element has a width that is between one mandrel width and three mandrel pitches.

FIG. 6 illustrates a possible layout conversion applied to layout of FIG. 2 using the various embodiments in this disclosure. Relationships between each adjacent active region pair and resulting connective elements are discussed in turn. Referring to FIG. 2, active regions 65 and 66 are adjacent and partially-parallel with a partially-parallel portion/region 71. The minimum distance 81 between the nearest sides is less than a specified minimum spacing. Referring to FIG. 6, connective elements 701, 703, and 705 are formed between the mandrels in the active regions 65 and 66 in the partially-parallel portion. Because the mandrel pitches are different, the connecting starts at the shortest mandrel end/end distance for connective element 705. From there, adjacent mandrels are connected as long as the angle is not limited by the photolithography process. Similarly to active regions 65 and 66, the partially-parallel region between active regions 66 and 67 are connected by connective elements 707 and 709.

As between active regions 66 and 63 and active regions 63 and 64, while the minimum distances 83 and 84 between the nearest sides are smaller than the specified minimum spacing for adjacent pairs of partially-parallel active regions, no connection is made because active region pairs are not partially-parallel since their mandrels are oriented orthogonal to each other. Note that the specified minimum distance only applies to distance between nearest sides of adjacent active regions where mandrels end. There is a different minimum value for 83 and 84 (mandrel end to run) below which the mandrel structures in adjacent active regions 66/63 and 63/64 cannot be formed. This different value is usually, but not always, less than the specified minimum spacing between the partially-parallel active regions, which would be mandrel end to end. Thus while no connective element is required between active regions 66 and 63 and between active regions 63 and 64 in accordance with various embodiments of the present disclosure, nevertheless other design rules may come into play regarding the spacing of these regions. On the other hand, active regions 64 and 68 are not partially-parallel because there are no overlapping regions even though the mandrels are parallel.

Connective elements between active regions 67 and 68 illustrate yet another embodiment of the present disclosure. Referring to FIG. 2, the minimum distance 86 between active regions 67 and 68 is greater than the specified minimum spacing; therefore, no connective element needs to be added in the partially-parallel region. However, as an option, the distance between active regions 67 and 68 can be reduced to less than or at the specified minimum spacing. By reducing the distance between various active regions, the size of the die may be reduced. Of course, once the minimum distance is reduced to below that of the specified minimum spacing, connective elements such as central connective element 711 and branch connective elements 713 are added as shown. Note that the decision whether to allow moving the active regions may also depend on the importance of reusing photomasks from other layers because the changed active region may result in different layouts in other layers.

FIG. 7 is a simplified diagrammatic view of a layout-generator 700 (or layout-generating machine). The layout-generator 700 includes a machine or tool that can be used to perform the layout conversion process discussed above in association with various figures. In an embodiment, the layout generator 700 includes a memory storage component 710 and a processor component 720. The memory storage component 710 is a non-transitory, tangible computer readable storage medium. For example, the computer readable storage medium may include a hard drive or a CD-ROM. The computer readable storage medium may be implemented as part of a single work station or may be implemented as part of a centralized server.

The computer readable storage medium stores instructions that can be executed by the processor 720. These instructions contain algorithms used to carry out the various steps of converting an initial layout having planar devices to a layout having FinFET devices, as discussed above. In one embodiment, the instructions contain these following algorithms that may each be implemented as part of a computer program. One such algorithm is implemented to carry out defining in each of the plurality of active regions a plurality of elongate mandrels that each extend in a first direction and are spaced apart from one another in a second direction perpendicular to the first direction. Another algorithm is implemented to carry out determining a minimum distance in the first direction between nearest sides between adjacent pairs of partially-parallel active regions. Yet another algorithm is implemented to carry out for each adjacent pair of partially-parallel active regions having a minimum distance less than a specified minimum spacing, connecting at least a portion of nearest ends of pairs of elongate mandrels from the adjacent pair of partially-parallel active regions. One more algorithm is implemented to carry out generating a second layout using a layout-generating machine, said second layout including the plurality of active regions, a plurality of elongate mandrels in the plurality of active regions, and connective elements between active regions of at least one adjacent pairs of partially-parallel active regions.

The instructions containing these algorithms are fetched from the computer readable storage medium to the processor component 720 for execution. After execution, the processor component 720 generates a new layout having FinFET devices. In other words, the planar devices from the initial layout are converted into the FinFET devices in the new layout through the execution of the instructions containing the above-mentioned algorithms. The new layout having FinFET devices may be stored in the memory storage component 710. It is understood that additional algorithms may be included in the instructions as part of this layout conversion process. These additional algorithms correspond to the various methods described above. It is also understood that the new layout having FinFET devices may be sent to a photomask fabricator so that photomasks corresponding to the new layout may be produced.

The embodiments of the present disclosure discussed herein offer several advantages, it being understood that other embodiments may offer different advantages, and that no particular advantage is required for any embodiment. For example, any given layout (such as a planar device layout) can be automatically converted into a FinFET device layout using the methods discussed herein. The entity (e.g., a design house) that generates the initial layout need not have the necessary tools to perform a FinFET layout and need not worry about meeting FinFET design rules. The entity (e.g., a foundry) that performs the above-described layout conversion will take care of the layout conversion from planar devices to FinFET devices in a seamless fashion. This enables the entity that generates the initial layout to have greater flexibility in performing the initial layout.

Although the embodiments and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. 

1. A semiconductor manufacturing method of generating a layout for a device, comprising: receiving a first layout, the first layout including a plurality of active regions, each active region having sides; for each of the plurality of active regions, defining a plurality of elongate mandrels that each extend in a first direction and are spaced apart from one another in a second direction perpendicular to the first direction, said first direction selected according to an elongate direction of a gate electrode; determining a minimum distance in the first direction between nearest sides between adjacent pairs of partially-parallel active regions; for each adjacent pair of partially-parallel active regions having a minimum distance less than a specified minimum spacing, connecting at least a portion of nearest ends of pairs of elongate mandrels, each mandrel of a pair from a different active region of the adjacent pair of partially-parallel active regions; and, generating a second layout using a layout-generating machine, said second layout including the plurality of active regions, a plurality of elongate mandrels in the plurality of active regions, and connective elements between active regions of at least one adjacent pair of partially-parallel active regions.
 2. The method of claim 1, wherein connecting at least a portion of nearest ends of pairs of elongate mandrels from the adjacent pair of partially-parallel active regions comprises: in a partially-parallel portion of the adjacent pair of partially-parallel active regions, selecting a pair of elongate mandrels across the nearest sides having a shortest distance between them; and starting from the selected pair of elongate mandrels, attaching a connective element to ends of each pair of elongate mandrels across the nearest sides within the partially-parallel portion of the adjacent pair of partially-parallel active regions.
 3. The method of claim 2, wherein the connective element has a width not greater than either mandrel between which the connective element connects.
 4. The method of claim 2, wherein the connective element is a straight.
 5. The method of claim 2, wherein the connective element is a curved.
 6. The method of claim 1, wherein connecting at least a portion of nearest ends of pairs of elongate mandrels from the adjacent pair of partially-parallel active regions comprises: forming a central connective element along the second direction between the adjacent pair of partially-parallel active regions; and attaching a branch connective element to each end of the nearest ends of pairs of elongate mandrels to connect to the central connective element; wherein the branch connective element extends in the first direction and is spaced apart from one another in the second direction perpendicular to the first direction, and wherein the pairs of elongate mandrels are within a partially-parallel portion of the adjacent pair of partially-parallel active regions.
 7. The method of claim 6, wherein the central connective element has a width not greater than two times that of mandrels in the adjacent pair of partially-parallel active regions.
 8. The method of claim 6 wherein the branch connective element has a width not greater than the mandrel end to which the branch connective element connects.
 9. The method of claim 1, further comprising: forming a photomask using the second layout.
 10. The method of claim 1, further comprising: depositing a plurality of mandrels and connective elements according to the second layout; depositing spacers around the plurality of mandrels; removing the mandrels; removing the connective elements; and, etching fins into a silicon layer using the spacers as a hardmask.
 11. The method of claim 1, wherein a pitch of mandrels in one active region of the adjacent pair of partially-parallel active regions is not the same as a pitch of mandrels in another active region of the adjacent pair of partially-parallel active regions.
 12. The method of claim 1, wherein a pair of elongate mandrels across the nearest sides having a shortest distance between them do not lie on the same line.
 13. The method of claim 1, further comprising: moving one active region of an adjacent pair of partially-parallel active regions having a minimum distance greater than a specified minimum spacing toward the other active region of the adjacent pair of partially-parallel active regions so that the minimum distance between the adjacent pair is equal to the specified minimum spacing.
 14. The method of claim 1, wherein the defining in each of the plurality of active regions a plurality of elongate mandrels comprises: defining a top elongate mandrel extending in a first direction disposed one fin thickness away from a top side of the active region; defining a bottom elongate mandrel extending in a first direction disposed one fin thickness away from a bottom side of the active region; defining a maximum number of elongate mandrels between the top elongate mandrel and the bottom elongate mandrel, wherein all mandrels in the active region are spaced apart equally from one another in a second direction perpendicular to the first direction and wherein the elongate mandrels are defined to have a pitch larger than a minimum pitch.
 15. A photomask comprising: a plurality of active regions; a plurality of mandrels in each of the plurality of active regions; and connective elements between active regions of at least one adjacent pair of active regions, wherein a shortest distance between the active regions of the one adjacent pair of active regions is equal to or less than a minimum spacing and wherein at least one mandrel from one of adjacent pair of active regions is parallel to at least one mandrel from the other of adjacent pair of active regions.
 16. The photomask of claim 15, wherein the connective elements comprises a central connective element and a plurality of branch connective elements, said branch connective elements being connected to the central connective element at one end and connected to an end of a mandrel from one of the active regions, and wherein the branch connective elements do not intersect each other.
 17. The photomask of claim 16, wherein the central connective element has a width not greater than about two times that of mandrels in the adjacent pair of active regions and wherein the branch connective element has a width substantially equal to the mandrel end to which the branch connective element connects.
 18. The photomask of claim 15, wherein the connective elements comprises a plurality of straight mandrels, each connecting one end of a mandrel in one active region to one end of another mandrel in the other active region, and wherein the plurality of straight mandrels do not intersect.
 19. The photomask of claim 18, wherein the connective element has a width not greater than either mandrel between which the connective element connects.
 20. The photomask of claim 15, wherein the connective elements comprises a plurality of curved mandrels, each connecting one end of a mandrel in one active region to one end of another mandrel in the other active region, and wherein the plurality of curved mandrels do not intersect. 